Probiotic bacteria are defined as live microorganisms which when administered in adequate amounts beneficially affect the host. Lactobacilli and bifidobacteria are the most frequently used bacteria in probiotic products. These bacteria are generally safe, as are probiotics based on these organisms. The lack of pathogenicity extends across all age groups and to immunocompromised individuals. Intake of different probiotic bacteria has been shown to have clinical benefits in various physiologic or pathologic situations. The most clear cut effects have been shown in diarrhea caused by antibiotic therapy or rotavirus infection. There are also studies showing positive clinical effects in inflammatory bowel diseases, atopic dermatitis and hypercholesterolemia after intake of probiotic bacteria. The mechanism, by which probiotic bacteria contribute to these clinical improvements are not clear. In vitro human, as well as both in vivo and in vitro animal studies have shown that different species of lactobacilli affects the innate and acquired immune system in many different ways. Clinical studies have mainly shown stimulation of the innate cellular immune system and enhancement of humoral immune responses to natural infections and systemic or oral immunisation. Regarding effects of the innate immune system, increased phagocytic activity of polymorphonuclear cells (PMN) and increased NK cell tumor killing activity have been reported. To our knowledge, there are no clinical studies showing effects on the specific cellular immune system after intake of probiotic bacteria.
According to the present invention the effects on the innate and acquired immune system following daily intake of lactobacilli or the Gram-negative bacteria P. lundensis have been thoroughly investigated. Interestingly, it has been observed an activation of the specific cellular immune system in subjects receiving L. plantarum and indications of such in subjects receiving L. paracasei. Moreover, immunity-enhancing effects on the innate immune system, such as expansion of the NKT cell population and increased phagocytic activity were observed in subjects receiving different lactobacilli species. Intake of the Gram-negative bacteria P. lundensis had no effects, whatsoever, on the different immune parameters measured according to the experiments described herein.
The development of antibiotic resistance and failures in various treatment of infections have risen an increased interesting in probiotics as an alternative tool. There might be a need for a probiotic functional food product targeting the common cold problem. It is clear in terms of the high number of incidence of cold infections every year. Traditionally foods with high levels of vitamin C have been taken to try to reduce the incidence of common cold. On the market there are a number of different products claiming some effect on the immune system.
The present application will aim to study if a probiotic functional food product after regular administrations could affect the common cold symptoms in a similar way and thus can be an alternative solution for this problem in the general community.